Hello, everyone! So to cut the story short I've been cruising around Mexico on my 1200gs and decided to have a service check at Mexico City dealer's. Looks like it was a serious mistake as now I have problems with my bike that I can't figure out myself. I'm near Cancun now and Cancun's dealer is said to be even worse, so I can rely on your advice only to fix it myself with those crippled hands of mine

The symptoms are the following:

1. When cold engine stalls and I need to rev up the gas in order to keep the RPMs
2. When on the first gear stalls frequently, overall RPMs are not stable and it gets worse
3. I can feel that output/power is much worse on both ends and it gets worse
4. Sound has changed - before I had exaust "caugh" only when I close gas, now it is all the time like series of caughs
5. Clutch became more tight - it is hard to hold it on first gear
6. When I try to move slower than the first gear allows using clutch there is SERIOUS vibration and "helicopterish" sound, engine stalls sometimes as well

My noob Hypothesis:

1. Smth with fuel/air mixture - need to check air filter, try without power commander (booster plug in my case), check injector (dunno how)
2. Exaust/CAT? I've been using mexican 92 fuel and 89 occasionaly. However, many ppl use the same bikes here without such problems and I didn't use unleaded fuel (which I'm not certain as they can add anything in fuel)
3. Clutch. But it doesn't hold for all the symptoms. However, I had my clutch steamed in the mountains once and asked those BMW guys to check it, they said it was OK

a) Like already mentioned above, a badly seated throttle cable.
It's possible one of the throttle cables has come partially dislodged and now the two cylinders are getting very uneven throttle.
That makes the engine run quite rough. Or,

b) My guess is that one of the stick coils is not properly connected to the ignition wire. Or worst, one stick coil was damaged when they pulled them out.
From the sound of it, your bike is running really badly so it's more likely one of the main spark plugs (as opposed to the secondary).

--
Mikko

__________________
"It is not when or how you die but how and if you truly were ever alive!"Dr. Jerri Nielsen FitzGerald

Now, to check if you have issues with the stick coils.
(I don't know how mechanically inclined you are, sorry if this is already obvious to you.)

The ignition coils ("stick coils") are INSIDE the valve covers, at ends of ignition wires, plugged onto the spark plugs. There are 2 plugs per cylinder, but based on the severity of the problem, I'd blame the main plugs - facing you, not the secondary plugs underneath cylinder heads.

Below is a picture from a spark-plug changing thread at r1200gs.info - this shows how to pop off the cover to access the stick coils.

Get the cover off and feel with your finger if the coils are solidly seated.

You can try pulling out the stick coil if unsure. You should have a little plastic coil-removal tool in your kit, otherwise use a screwdriver as shown here. Be careful, go easy to avoid ripping up the coil head (I'd use 2 screwdrivers) and make sure to protect the valve cover with something soft, like the cloth shown here.

Or, use the wire method:

If the coils are seated, one of them could still be faulty. One method to check that is to disconnect one of the coils wires, tape up the end and start the bike. If it is much worse, you disconnected a working coil. If there is no change in behavior, you disconnected a coil that was not working.

Here is a picture from JVB's post that shows the top of stick coil and the connector that needs to be undone to disconnect the wire. There is a little tab on the connection - pry it up slightly with a small screwdriver and then pull out the connector away from the coil.

I hope this helps in your troubleshooting. Since you believe that the problem started with the service, I'd look at things that were disturbed during the work (like the throttle cables or the coil sticks), before worrying about actual component failures.

Everybody's dead on with the advice, trace back what's been touched before you touch anything else. Don't get ahead of yourself, take time to do this right and don't make stuff worse in panic. Lay everything out on a towel or tshirt (don't lose stuff in the dirt), take lots of pictures of start to finish what you do so you can back track. Where i'm at in Africa it's best to keep the local mechanics away if it's more than patching a tube. Most of all good luck!

Everybody's dead on with the advice, trace back what's been touched before you touch anything else. Don't get ahead of yourself, take time to do this right and don't make stuff worse in panic. Lay everything out on a towel or tshirt (don't lose stuff in the dirt), take lots of pictures of start to finish what you do so you can back track. Where i'm at in Africa it's best to keep the local mechanics away if it's more than patching a tube. Most of all good luck!

+1 +1 +1

Exactly! We all have been there, trashing around, suspecting total breakdowns, multi-$$$$ repairs - while only a small item was missing (omitted by ourselves or even a skilled mechanic).

Relax, have a nice drink, think things through. I cannot emphasize enough that the troubleshooting should follow a bit of detective work regarding recent service.